Organic Light Emitting Diode (OLED), found in the year of 1987 in lab, has been developed remarkably in recent years. Compared with liquid crystal panels, AMOLED has many advantages such as autoluminescence, high contrast, wide viewing angle, low temperature resistance and flexibility. The OLED is a current-driven autoluminescent material, while organic material and metallic cathode are apt to be eroded by water and oxygen and an OLED element may consequently not function normally. In related procedure of manufacturing an OLED display, usually, two glass substrates or two flexible substrates are used, and the OLED element is sandwiched between the two substrates through packaging process, thereby protecting the OLED element from being eroded by water and oxygen.
During an evaporation process for the OLED element, an evaporation glass substrate is arranged with its front downward. After the evaporation process, the evaporation substrate is to be attached to a packaging substrate. Since the OLED element, made of the organic material and cannot be pressed by hard objects, is provided on the evaporation substrate, the evaporation substrate transferred into a device is supported by a peripheral supporter. Then, an upper machine table goes down close to the evaporation substrate and absorbs the evaporation substrate via vacuum absorption. The packaging substrate is placed on a lower machine table. When attaching the evaporation substrate to the packaging substrate, the peripheral supporter is removed and the evaporation substrate absorbed by the upper machine table goes down to attach to the packaging substrate.
In the above evaporation process, no supporter is arranged at the center of the evaporation substrate and the evaporation substrate is merely supported by the peripheral supporter. Due to gravity of the evaporation substrate and stresses generated in prior processes, the center of the evaporation substrate may droop more or less. In the case that the center of the evaporation substrate droops a lot, the upper machine table cannot absorb the evaporation substrate via vacuum absorption, which may adversely affect the attaching process.